Sieburg, Anne ; Jochum, Tobias ; Trumbore, Susan E. ; Popp, Jürgen ; Frosch, Torsten (2017)
Onsite cavity enhanced Raman spectrometry for the investigation of gas exchange processes in the Earth's critical zone.
In: Analyst, 142 (18)
doi: 10.1039/c7an01149k
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
Raman gas spectrometry is introduced as a robust, versatile method for onsite, battery-powered field measurements of gases in the unsaturated and saturated critical zone. In this study, depth-profiles of the concentrations of oxygen and carbon dioxide were simultaneously monitored down to ∼70 meters depth in the subsurface via a transect of drilling holes located in the Hainich Critical Zone Exploratory in central Germany. A special multichannel monitoring system was designed to access and analyze these gases non-consumptively onsite in a closed loop measurement cycle. During the timeframe of six months, seasonal changes in groundwater levels and microbial activity were related to changes observed in gas concentrations. High oxygen concentrations were found in the depths surrounding a karstified aquifer complex, while low oxygen concentrations were found in a fractured aquifer complex. Raman gas depth-profiles complement standard dissolved oxygen measurements as they also deliver oxygen concentrations in the unsaturated zone. The measured depth-profiles of the gas concentrations indicated that regions of anoxia can exist between the aquifer complexes. Lateral transport of O2 in the deeper aquifer complex provides a local source of O2 that can influence metabolism. Correlations were found between the observed CO2 concentrations and pH-values, indicating strong control of carbonate equilibria. The concentrations of O2 and CO2 were largely decoupled, thus simultaneous measurements of O2 soil effluxes give additional insights into biotic and abiotic processes in the Hainich CZE. These results illustrate the versatility of robust onsite Raman multigas measurements of the soil atmosphere and how they can contribute to the analysis of complex processes in previous uncharacterized environments in the critical zone.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 2017 |
| Autor(en): | Sieburg, Anne ; Jochum, Tobias ; Trumbore, Susan E. ; Popp, Jürgen ; Frosch, Torsten |
| Art des Eintrags: | Bibliographie |
| Titel: | Onsite cavity enhanced Raman spectrometry for the investigation of gas exchange processes in the Earth's critical zone |
| Sprache: | Englisch |
| Publikationsjahr: | 30 August 2017 |
| Verlag: | Royal Society of Chemistry |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Analyst |
| Jahrgang/Volume einer Zeitschrift: | 142 |
| (Heft-)Nummer: | 18 |
| DOI: | 10.1039/c7an01149k |
| Kurzbeschreibung (Abstract): | Raman gas spectrometry is introduced as a robust, versatile method for onsite, battery-powered field measurements of gases in the unsaturated and saturated critical zone. In this study, depth-profiles of the concentrations of oxygen and carbon dioxide were simultaneously monitored down to ∼70 meters depth in the subsurface via a transect of drilling holes located in the Hainich Critical Zone Exploratory in central Germany. A special multichannel monitoring system was designed to access and analyze these gases non-consumptively onsite in a closed loop measurement cycle. During the timeframe of six months, seasonal changes in groundwater levels and microbial activity were related to changes observed in gas concentrations. High oxygen concentrations were found in the depths surrounding a karstified aquifer complex, while low oxygen concentrations were found in a fractured aquifer complex. Raman gas depth-profiles complement standard dissolved oxygen measurements as they also deliver oxygen concentrations in the unsaturated zone. The measured depth-profiles of the gas concentrations indicated that regions of anoxia can exist between the aquifer complexes. Lateral transport of O2 in the deeper aquifer complex provides a local source of O2 that can influence metabolism. Correlations were found between the observed CO2 concentrations and pH-values, indicating strong control of carbonate equilibria. The concentrations of O2 and CO2 were largely decoupled, thus simultaneous measurements of O2 soil effluxes give additional insights into biotic and abiotic processes in the Hainich CZE. These results illustrate the versatility of robust onsite Raman multigas measurements of the soil atmosphere and how they can contribute to the analysis of complex processes in previous uncharacterized environments in the critical zone. |
| Freie Schlagworte: | Onsite, Cavity Enhanced Raman Spectroscopy CERS, Environmental Gas Sensing, Ecological Gas Sensing, Gas Analysis, Critical Zone, Depth Profiles, Gas Exchange Processes |
| Fachbereich(e)/-gebiet(e): | 18 Fachbereich Elektrotechnik und Informationstechnik 18 Fachbereich Elektrotechnik und Informationstechnik > Biophotonik-Medizintechnik |
| Hinterlegungsdatum: | 18 Jan 2024 11:37 |
| Letzte Änderung: | 14 Mär 2024 10:21 |
| PPN: | 516292617 |
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